Next, I created a histogram with average #nicar18 tweet counts by hour for the three full days: Thursday, Friday and Saturday. It shows when people sent the most tweets — and that they apparently took more breaks during lunch and just before the first afternoon sessions began.

The pattern is also clear here in a more granular view of daily tweet counts by hour:

This tweet volume, which only captures people tweeting with the hashtag, was posted by attendees from across the globe. This year’s conference, as I mentioned in the previous post, had record-breaking attendance: more than 1,200.

Here’s where the attendees came from:

These types of maps are imperfect, of course, especially on mobile. For one, it’s tough to decipher attendance from the Northeast and Mid-Atlantic regions.

Here’s a more focused version (still a little nuclear blasty), if that helps (please note that the scale is different from the map above):

I’m in the United States this week to attend the annual news nerd conference known as NICAR, a diverse gathering of reporters, editors and developers (and others) focused on storytelling with data.

I look forward to it like Christmas.

I get to return to the United States, see old friends, learn new skills and drink Diet Coke, which is nearly impossible to find in South Korea, where I work as a foreign correspondent for the Los Angeles Times.

These basic graphics help explain the event, held this year in Chicago.

First, there’s record-breaking attendance* this year:

The event has more than 200 sessions over five days, from the basic use of spreadsheets in news gathering to the construction of complex news applications — and the organizers (who graciously share data about the conference) categorized them by type:

The conference generally has a mix of skills sets and expertise levels, which is evident in the session categories:

There are people here from almost every American state and from numerous countries around the world. My jet lag brain is still working through how to best visualize that, perhaps in a map. I’ll post something soon.

I’ve often felt fortunate that I get to write about South Korea for the Los Angeles Times, a newspaper that’s still interested in stories related to life, politics and culture here — not just the strongman to the North.

That interest is in part because the Times remains a serious paper that’s trying to stay committed to foreign news, but also because a decent portion of its readers are Korean. The Los Angeles metro area, for example, has more than 340,000 people of Korean descent, about a fifth of the overall Korean population in the United States, according to the U.S. Census Bureau.

I’ve written before about South Korean expatriates overseas. These maps, however, show the population of all ethnic Koreans who have settled in Los Angeles and across the United States.

Let’s start with Los Angeles and a caveat: I may write for the Times, but I don’t yet know its geography (especially not like thesefine folks).

This map shows Los Angeles County, which has about 230,000 people of Korean ancestry, according to the 2010* Census. The deep teal colors in the center of the county reflect the population of Koreatown, a neighborhood inside the city of Los Angeles. This place is legit Korean. There’s even a Paris Baguette! There are several suburban areas, such as Glendale, north of Koreatown, that also have a relatively high proportion of Korean residents.

This map shows the Korean share across the country, by county. Most counties have tiny proportions of Koreans. (My home county in East Texas had a grand total of 194 Koreans, or about 0.16 percent of its population). Other areas, such as Southern California, the mid-Atlantic coast and the New York metro area have comparatively large Korean populations.

This map uses the same data set but a different visualization technique — proportional symbols, not shaded county boundaries. Larger symbols, or bubbles, represent a higher number of Koreans in raw figures, not proportions.

And, finally, here are two tables with the top 25 counties by both measures — proportion and population:

* I chose this data set because it was the last hard count of all Americans by the Census Bureau. The agency also conducts large, quality surveys between each decennial census, but detailed questions, such as specific ancestral or ethnic origin, can come with high margins of error at smaller geography levels. The hard count also isn’t perfect, but it’s the best we have for national county-level maps until 2020.

Another North Korean soldier defected at the Demilitarized Zone on Thursday, causing a brief skirmish along the highly fortified border. He was the fourth solder to defect this year, including the one last month who was shot several times by his comrades before he made it to safety in South Korea.

There have been tens of thousands of defections from the communist regime since the 1953 armistice that ended the Korean War. Most don’t occur at the DMZ, a 2.5-mile buffer zone filled with landmines, guard posts and barbed wire.

Here’s a look at some of the demographics of those North Koreans who defected over the years.

This first chart shows the numbers of defectors since 2001, by gender. You can see that women have been more likely to defect — and that there was a sharp drop-off in defections beginning in 2012. That’s the year that Kim Jong Un, the grandson of North Korea’s founder, Kim Il Sung, took power. Coincidence? Probably not.

This next bar chart shows the defector counts by age groups, again while breaking out gender. It’s easier to defect when you’re young, I suppose.

And, finally, a provincial map showing where known defectors came from, with darker shades representing more defections. North Hamgyong Province had the most (more than 18,000), probably because defectors can sneak across the Tumen River — which forms about a third of the border between China and North Korea.

A few weeks ago I wrote about the daring defection — and eventual rescue — of a North Korean soldier who barreled across the Demilitarized Zone in a truck and then ran as fellow troops fired on him. The story centers on a dramatic video of the ordeal released by United Nations command.

The video, shot the afternoon of Nov. 13, shows the soldier speeding down a road toward the Joint Security Area, a border outpost that’s been the site of military skirmishes and diplomatic talks between the Koreas, still technically at war, and the U.S.

The soldier can be seen driving in a green military-style vehicle past a North Korean checkpoint before wheeling past a monument inside the area, where soldiers from both sides of the conflict are posted in relatively close proximity. The footage is a series of videos taken from different cameras at different angle.

The video fascinated me, but I found myself wanting someone to explain the sequences more clearly, so I started crafting a graphic in my free time to annotate the defector’s journey. I tried this using the ai2html tools created by The New York Times that are built into NPR’s dailygraphics rig. After a visit to the location with United States forces last week, I’m confident the graphic is accurate. I’m less confident, unfortunately, in its storytelling, design or technical merit.

Oh, well. Your first try with a new tool is never perfect — especially when this work is just a hobby.

Try it on desktop, tablet and mobile — and let me know if you have thoughts.

Despite international objections, North Korea has launchedfour ballistic missiles in the last week, including one that flew over Japan, raising regional tensions about the rogue state’s weapons development even higher.

For those of us who live in South Korea, such provocations have become commonplace, especially since the North’s new leader, Kim Jong Un, took over after his father’s death in late 2011. They interrupt Sunday breakfasts or even national holidays, but they haven’t yet seemed like a real threat.

(Of course, they can just use their ample artillery along the border to strike Seoul, where I live).

The missile testing pace and the North’s increasingly technically ability have increased significantly in the last years, however, causing more and more heartburn in the region.

This chart shows the pace of testing over the years, including missiles that “failed” in flight:

The North has over the years developed (and borrowed) its own set of missiles, each with varying capabilities. Lately they’ve grown more powerful, though not always reliable.

Here’s how often they’ve used them, by missile type:

Since 1984, there have been at least 115 missile launches. But those tests have come from a select group of locations around the North: airfields and testing sites. Here are those tests locations, aggregated, with larger bubbles representing more launches:

And this map shows each launch in time order, with a flurry beginning in 2013. Colors change based on the missile type:

This is just a quick post, created largely because I wanted to build another proportional symbols map with D3. For a more thorough analysis, check out this post.

The students, working journalists and professors, were quite impressive. Working in groups, they created several data-driven projects of their own — a few of which were publishable after just a few days’ work.

For a mapping exercise, students identified several locations by latitude and longitude.

Students demo their project related to Chinese perception of the U.S. presidential election.

I love China, and it was a real honor to be invited to work with such talented group. 谢谢

The folks at FiveThirtyEight had a fun data visualization discussion during their regular election chat this week, about whether Hillary Clinton should focus on ensuring victory next month or spending more money in “red” states to expand her Electoral College map.